A sensitivity analysis for the design of small-scale hydropower plant: Kayabogazi case study

In this study, the feasibility of hydroelectric power generation from the Kayabogazi dam, which was built by The State Hydraulic Works of Turkey (DSI) in 1987 in the town of Tavsanli, Kutahya, for irrigation and flood control purposes is investigated. Since a certain amount of water is supplied from the dam to the town of Tavsanli as drinking water, that amount is deducted from the total and is not allowed to be used in the process of electric power generation. By evaluating the amount of incoming water to the Kayabogazi dam in the period of 1995 and 2003 years, the most agreeable turbine type and size is decided for a small hydropower plant (SHP). In this purpose, seven different cases have been taken into consideration. As a conclusion, the case used three turbines which one of them is installed to utilize from the higher flow rates has been determined as the best configuration. In this study, a power generation ranging between 0.313 and 4.997 MW has been achieved in the viewpoint of installed capacity for Kayabogazi dam. Hence, it has been estimated an electricity generation up to 10,579 MWh per annum.     

Impact of extreme donor age on the outcome of living-related donor kidney transplantation

Eosinophil cationic protein (ECP) in sputum may be used to estimate the severity of bronchial inflammation and obstruction in asthmatics as well as to monitor asthma drug therapy. For this purpose, standardized processing of sputum is important. The aim of our study was to determine whether time and temperature influence the ECP concentration in the sputum of asthmatics. The samples of induced sputum obtained from 12 patients with stable asthma were homogenized using ultrasonification, and centrifuged. Supernatants were evenly divided and stored for 1, 6, 24 or 72 h at either 4 or 25 degrees C, then frozen at -80 degrees C. The ECP concentrations were determined using fluoroimmunoassay and compared with the immediately frozen samples. After storing at 4 degrees C, the ECP levels at the four time points were 101.2, 96.0, 98.2 and 90.6% of the initial concentration, respectively. When sputum specimens were stored at 25 degrees C, ECP levels decreased to 96.1, 94.4, 90.7 and 87.7%, respectively. The influence of time on ECP concentrations in sputa was statistically significant (p=0.02). A significant temperature effect was found when comparing the specimens stored at 4 degrees C with those at 25 degrees C (p=0.03). Looking at individual time points, a significant decrease in ECP concentration was only seen at 25 degrees C after 24 and 72 h. We conclude that eosinophilic cationic protein in the sputum of asthmatics decreases in a time- and temperature-dependent process. If sputa cannot be processed after obtaining the specimens, they should be stored in a refrigerator at 4 degrees C, until eosinophilic cationic protein is measured.     

Designing cost-effective content distribution networks

In this paper, we present a novel technique for the problem of designing a Content Distribution Network (CDN), which is a technology used to efficiently distribute electronic content throughout an existing IP network. Our design proposal consists of jointly deciding on (i) the number and placement of proxy servers on a given set of potential nodes, (ii) replicating content on the proxy servers, and (iii) routing the requests for the content to a suitable proxy server such that the total cost of distribution is minimized. We model the problem using a nonlinear integer programming formulation. The novelty of the proposed formulation lies in simultaneously addressing three interdependent problems in this context as well as explicitly representing the distribution structure of a CDN through the objective function. We offer a linearization for the model, develop an exact solution procedure based on Benders’ decomposition and also utilize a variant of this procedure to accelerate the algorithm. In addition, we provide a fast and efficient heuristic that can be used to obtain near-optimal solutions to the problem. Finally, the paper concludes with computational results showing the performance of the decomposition procedure and the heuristic algorithm on randomly generated Internet topologies.     

Enhanced gas barrier and mechanical properties in organoclay reinforced multi-layer poly(amide-imide) nanocomposite film

Multifunctional single and triple-layer films exhibiting flexibility, enhanced modulus and gas barrier properties were developed using a soluble polyamide-imide (PAI) in dimethylacetamide (DMAc) with ammonium-modified montmorillonite (MMT, Cloisite 30B) mineral clay. The drying behavior and associated anisotropy development were determined real-time, using a newly developed real-time measurement system. Out-of-plane birefringence development takes place earlier for thinner neat samples caused primarily by increased depletion rate of solvent. Addition of organoclay content resulted in a decrease in evaporation rate of solvent due to planar orientation of well exfoliated nanoplatelets as shown by TEM images and WAXS. This is in agreement with the out-of-plane anisotropy development observed during drying. Beyond a critical solid wt%, out-of-plane birefringence started to increase earlier with organoclay addition. In the case of multi-layer organoclay reinforced PAI films, the drying behavior of each individual layer was tracked and a complementary drying model is proposed. Planar orientation of nanoplatelets resulted in high helium-barrier properties.     

State-led Urban Regeneration in Istanbul: Power Struggles between Interest Groups and Poor Communities

From the early 2000s, urban policy-makers in Turkey have promoted ‘urban regeneration’ as the main tool to transform low-income housing areas, along with former industrial estates, disused port facilities and so on, into modern living, working, shopping and entertainment areas. The intention has been to boost land and property values by transforming both the physical appearance and the sociocultural and class composition of selected sites. But while the impact, the rationale and the outcomes of urban regeneration in Turkey are broadly similar to those reported in the substantial global literature on ‘urban regeneration’, a case-study approach shows that a number of crucial context-specific factors have shaped the assumption and responses of key players and collective actors. These in turn have determined how ‘regeneration policies’ are finally translated into practice. This article illustrates this point by describing a particular recent case study in Istanbul: the Tozkoparan Regeneration Project.     

Directed Electric Field Z‐Alignment Kinetics of Anisotropic Nanoparticles for Enhanced Ionic Conductivity

In this study, the fast transient evolution of the electric field assisted thickness Z‐direction orientation and assembly of clay particles is studied using a instrumented real time system that simultaneously measures in‐plane and out of plane birefringence. The optical anisotropy master curves are developed, connecting the exposure time and electric field strength with orientation, using a superposition principle. Z‐oriented nanocomposite films manufactured through the R2R process show enhancement through thickness ionic conductivity, useful for membranes of batteries and fuel cells.     

Effect of liquid characteristics on the wetting,capillary migration,and retention properties of fibrous polymer networks

Fluid penetration through porous networks consists of two different phenomena: (1) pore fluid displacement and (2) fluid flow through the pores. The first phenomenon depends on the pore size, the fluid–fluid interfacial tension, and the contact angle. The second phenomenon is pore‐size‐ and viscosity‐dependent. We adapted an experimental methodology often used for measurements of liquid permeability and hydraulic conductivity of soils and applied it to polymeric medical textiles. The methodology made use of a pressure/flow cell in which a sample was mounted. The flow rates were measured during sequences of increasing and decreasing pressures applied to the displacing nonwetting fluid (aqueous solution). The effects of the liquid parameters on penetration were investigated. Surface tension effects were studied with water and two solutions with surface tensions lower than that of pure water; the liquids with lower surface tensions had lower displacement pressures. To study viscosity effects, we used water and two solutions with viscosities higher than that of pure water. Increasing the viscosity not only caused the flow rate to decrease but also caused deformation, that is, enlargement, of the pores. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 282–292, 2005     

Disruptions to women's social identity: A comparative study of workplace stress experienced by women in three geographic regions.

Drawing on social identity theory (P. J. Burke, 1991) and the current status of women and equal opportunity legislation, the authors tested several factors associated with distress in working women in the People's Republic of China (PRC), Hong Kong, and the United States. Women in Hong Kong experienced significantly greater levels of life stress than PRC and U.S. women. Reports of negative attitudes toward women, gender evaluation, and avoidance coping were greater for Hong Kong and PRC women than for U.S. women. Hong Kong women reported more use of positive/confrontational coping mechanisms. Negative attitudes toward women had an important influence on life stress across regions. Moderator tests resulted in 2 significant findings: The effect of negative attitudes toward women on life stress was stronger for PRC and Hong Kong women, and the relationship between nervous/self-destructive coping and life stress was stronger for U.S. women. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Optimization of the transmitter-receiver separation in the ground-penetrating radar

The finite-difference time-domain method is applied to simulate three-dimensional subsurface-scattering problems, involving a ground-penetrating radar (GPR) model consisting of two transmitters and a receiver. The receiving antenna is located in the middle of the two identical transmitters, which are fed 180/spl deg/ out of phase. This configuration implies the existence of a symmetry plane in the middle of two transmitters and the cancellation of the direct signals coupled from the transmitters at the receiver location. The antenna polarizations and their separations are arbitrary. The transmitter-receiver-transmitter configured GPR model is optimized in terms of the scattered energy observed at the receiver by varying the antenna separation. Many simulation results are used to demonstrate the effects of the antenna separation and the optimal separation encountered for a specific target and GPR scenario.     

Visualization of the Equilibrium FCC Catalyst Surface by AFM and SEM–EDS

The deposition of metal contaminants (e.g., Ni, V, and Fe) from the hydrocarbon feed causes the deactivation of fluid catalytic cracking (FCC) catalyst used in petroleum refining. It is very important to understand the changes in the morphology and chemical composition on the catalyst surface and how these structural and chemical changes affect the catalyst performance. In this research, metal-contaminated FCC catalysts from a commercial unit have been characterized using AFM together with SEM–EDS. The AFM images showed the surface pores as well as the features that surround the pore's entrance on the catalyst surface. Catalyst surface contains debris that appear as bright spots in AFM images. SEM–EDS results have shown the presence of iron in these bright spots. Fe enrichment at the catalyst particle surface was also confirmed by XPS analyses.